Rose,
I'm so sorry you are going through this.
As Minspain said, therapy is a way for you to feel like you did everything you could, but I wouldn't count on it being much more than that. Therapy only effects change in those who want to change and are willing to do what is necessary to effect change even when it hurts. That's a tall order for a BPD.
My BPDh is in DBT therapy. To the best of my knowledge, he is only doing it because he thinks that if he "checks the box" of having completed DBT I will come back to the marriage (we've been separated for 6 months). If that is, indeed, his perspective on DBT, he will not experience the change that is necessary for me to feel I can trust him enough to return to the marriage.
I also have experienced what Minspain describes with BPDh taking the attitude of "I'm doing therapy. Why aren't you working on YOUR stuff?" He has literally said "I'm working harder than you". I happen to be meeting with a therapist 2x/month and have regular contact with trusted friends who will point out "my stuff" and encourage me to work through it, but there's no point in arguing that I'm "working on my stuff", much less getting into a debate about who is working harder.
I just came across this article in the BPD archives last night -
https://web.archive.org/web/20161021014801/https://bpdfamily.com/bpdresources/nk_a118.htmIt was written by a recovered BPD and talks about how to know if your BPD is serious about therapy and the dos and don'ts for helping them through therapy. It might be a good place to start if you want to consider therapy.
Also - if you do have your pwBPD start therapy, make sure the therapist has experience with BPD. There are therapists who will drop a patient if they are diagnosed BPD. For continuity of care and effectiveness of therapy, you need a therapist who knows what they are getting into.
BG